Oxidation stability has been identified as a very important performance for an oil product. For example, to nearly all types of lubricant oil products, an antioxidant is added as an essential component, so as to elongate its serve life. Further, with the rapid development of the modern automobile industry and machinery industry, the power output from engines and that input into mechanical machines have been dramatically increased, and as a result, the temperature at which lubricant oils work has been significantly increased, which exacerbates the oxidation problem. At the same time, as the quality grade of lubricant oils improves, it is needed to further lengthen the change-oil cycle, which sets an even higher demand on the oxidation stability (at elevated temperatures) of lubricant oil products.
In order to met these requirements set by the prior art, the technicians have been working on developing novel compounds having improved performance in oxidation resistance, so as to improve the oxidation stability of oil products. U.S. Pat. No. 5,304,314 discloses a phenol compound containing S and an aromatic amine moiety to be used as an antioxidant. US patent application No. 2006/0189824A1 discloses a hindered phenol compound containing a secondary aromatic amine moiety to be used as an antioxidant. Canada patent No. 1219584 discloses a hindered phenol compound containing S and a tertiary aromatic amine moiety to be used as an antioxidant. However, there still remains much room for the prior art compounds to be improved in oxidation resistance at elevated temperatures.
Therefore, there still remains a need for a novel compound, which exhibits significantly improved oxidation resistance at elevated temperatures as compared with prior art ones.